Having shown that "nonsterilizing immunity" in malaria is an antibody independent phenomenon, we will now investigate the immune mechanisms involved. T cell reactivity in vivo to malarial antigen will be stimulated by sensitizing chickens with Plasmodium gallinaceum suspended in complete Freund's adjuvant. Assorted antigenic preparations will be used to elicit positive skin tests. Active preparation will then be employed to assess T cell reactivity in vitro by demonstrating the specific production of MIF by spleen cells obtained from infected birds at various intervals of time after infection. Since hyperactivity of the reticuloendothelial system may be associated with "nonsterilizing immunity" to malaria, we will compare macrophages obtained from infected birds and normal birds for their ability to phagocytize and destroy salmonella in vitro. These studies will help to establish the role of T cells in the development of "nonsterilizing immunity" in avian malaria. BIBLIOGRAPHIC REFERENCES: Rank, R.G. and Weidanz, W.P. 1976. Nonsterilizing immunity in avian malaria - an antibody independent phenomenon. Proc. Soc. Exp. Biol. and Med. 151: 257-259. Maguire, H.C , Rank, R.G., and Weidanz, W.P. 1976. Allergic contact dermatitis to low molecular weight allergens in the chicken. Int. Arch. Allergy. In press.